Concentric valve internal combustion engine



June 13, 1961 T. E. NElR CONCENTRIC VALVE INTERNAL COMBUSTION ENGINE 7Sheets-Sheet 1 Original Filed Sept. 26, 1955 INVENTOR TH ERON E. NEI RATTORNEY June 13, 1961 T. E. NEIR CONCENTRIC VALVE INTERNAL COMBUSTIONENGINE 7 Sheets-Sheet 2 Original Filed Sept. 26, 1955 m ulh INVENT ORTHERON E. NEIR ATTORNEY June 13, 1961 T. E. NEIR 2,988,071

CONCENTRIC VALVE INTERNAL COMBUSTION ENGINE Original Filed Sept. 26,1955 7 Sheets-Sheet 3 L 5 kiss 1 Q s s v i 4 r t t l INVE OR 'Q I THERONE. NEIR ATTORNEY June 13, 1961 T. E. NEIR 2,988,071

CONCENTRIC VALVE INTERNAL COMBUSTION ENGINE Original Filed Sept. 26,1955 7 Sheets-Sheef. 4

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W a w aim D fiihi fr THERON E. NEIR ATTORNEY June 13, 1961 T. E. NElR2,988,071

CONCENTRIC VALVE INTERNAL COMBUSTION ENGINE Original Filed Sept. 26,1955 7 Sheets-Sheet 5 INVENTOR THERON E. NEIR ATTORNEY June 13, 1961 T.E. NEIR CONCENTRIC VALVE INTERNAL COMBUSTION ENGINE Original Filed Sept.26, 1955 7 Sheets-Sheet 6 INVENTOR THERON E. NEIR ATTORNEY June 13, 1961T. E. NEIR 2,988,071

CONCENTRIC VALVE INTERNAL COMBUSTION ENGINE Original Filed Sept. 26,1955 7 Sheets-Sheet 7 CLOSERBB Xmas 9 WT! lNLET VALVE OPENERS 84- VALVEINLET VALV INVENTOR THERON E. NEIR w ATTORNEY lllllllll States Originalapplication Sept. 26, 1955, Ser. No. 536,614. Divided and thisapplication Feb. 10, 1958, Ser. No.

7 Claims. (Cl. 123-79) The present invention relates to a new andimproved internal combustion engine of the concentric valve type. Thepresent engine is conventional to the extent that it utilizes suchcomponents as pistons, poppet valves, spark plugs and their normalaccoutrements, however, the components have been improved and combinedin such a way as to result in a novel and highly improved engine. Thisis a division of Serial No. 536,614, filed September 26, 1955.

The ultimate aim in the design of any internal combustion engine is theattainment of maximum power output per pound of engine weight. In thecase of conventional piston type engines, the point has practically beenreached where it is unlikely that any appreciable increase in the powerto weight ratio will be made with available materials. It is for thepurpose of increasing this ratio, as well as reducing engine size,complication and expense, that the present invention has been developed.

Essentially, the present engine includes a pair of concentricallyrelated inlet and exhaust valves mounted in the cylinder head above eachcylinder. From this point forward, however, the present enginerepresents a series of improvements designed to achieve the generalobjects hereafter set forth.

Since the power an engine can produce is proportional to the amount ofair that can be packed into the combustion chamber, it is a primaryobject of this invention to provide a valve and air manifold arrangementthrough which exceptionally large quantities of combustible charge canbe delivered per cycle to the combustion chamber.

In the present concentric valve engine it is only necessary to provide asingle valve opening or seat in the cylinder head to accommodate thevalves, therefore, the valve seat or opening may be of at least twice aslarge a diameter as is the case with an engine using side by sidevalves. Thus, the first advantage inherent in the present engine is thatan air inlet opening may be provided which, due to its increased area,will admit a considerably larger quantity of air than is possible with aconventional type engine.

Further, it is proposed to provide an air inlet passage whichcircumferentially communicates with the inlet valve in such a manner asto impart a tornado or tangential swirl to the combustion charge beforeit enters the combustion chamber. Additionally, a venturi means isprovided in the inlet passage to increase the velocity of the charge,the velocity-ram effect of which, in combination with the tangentialswirl, provides appreciable self-supercharging.

As a further means of increasing the quantity of combustible chargewhich may be delivered to the combustion chamber, a unique cam shaft androcker arm mechanism is provided which positively opens and closes thevalves. By this device it is possible to realize a greater valve openarea per cycle, resulting in an increased volumetric efiiciency.

Another basic object of the present invention is the provision of an aircooling system which uniquely cools the valves and exhaust manifoldingin a way to enable the use of less heat resistant, and consequentlylighter and cheaper materials. The cooling system derives itscirculatory momentum by communicating with the exhaust passage whicheducts the cooling air through and across the engine components to becooled. In order to multiply the eductive effect on the coo-ling system,as well as to provide better scavenging of the combustion cham ber,venturi means is provided in the exhaust passage to increase the exhaustgas velocity. In addition to more effective valve cooling, an advantagerealized in utilizing the instant air cooling system is a considerablereduction in the size and weight of the cylinder head. This reduction ispossible mainly because fewer cored water passages are necessary.

Additional objects will be apparent from a perusal of the structural andfunctional details set forth in the specification appended hereto.

In the drawings:

FIG. 1 is a plan view of the engine particularly showing the intake andexhaust manifolds.

FIG. 2 is an elevational view of the exhaust manifold side of theengine.

FIG. 3 is a cross-sectional view showing in elevation the overallarrangement of the engine components.

FIG. 4 is a plan cross-section through the cylinder head particularlyshowing the relationship between the air valves and inlet air passage.

FIG. 5 is an elevational cross-section showing the spark plugorientation with respect to the inlet Valve and piston.

FIG. 6 is a plan view indicating the spatial relationship between anexhaust pipe and a spark plug recess.

FIG. 7 is an enlarged view of the air valves particularly indicating theair cooling passages as well as the valve actuating collars.

FIG. 8 is a partially sectioned plan view of the valve actuatingmechanism.

FIG. 9 is an elevational view of the valve actuating mechanism.

FIG. 10 is a vertical cross section through the intake and exhaust valverocker arm shafts.

FIG. 11 shows a modified form of the valve actuating mechanism utilizinga four cam arrangement.

FIG. 12 represents a modification in which an oil filter is added to theair cooling system.

FIG. 13 shows a valve adjusting tool.

FIG. 14 represents a modified form of valve collar utilizing a lockingdevice.

General arrangement Referring to FIG. 3 of the drawings the upperportion of an engine is shown generally at 11 and includes a cylinderhead 12 suitably connected through studs 13 to a cylinder block 14.Reciprocally disposed within the block 14 are pistons 16. The engine isof the overhead valve type and includes concentrically related intakeand exhaust valves 17 and 18 disposed directly over piston 16.

Rockably mounted in head 12 are .rocker arms 19 and 21 adaptedrespectively to actuate the intake and exhaust valves 17 and 18. A camshaft 22 is operatively driven, in any convenient manner, by a crankshaft and in turn actuates the rocker arms 19 and 21 through suitablyprovided cams.

The head of piston 16 is centrally depressed at 23 and cooperates withthe superadjacent portion of the cylinder head 12 to provide acombustion chamber 24. The combustible charge for the engine is suppliedthrough an intak passage 26 while the exhaust gases are evacuated fromthe engine through an exhaust passage and manifold 27 and 28.

Intake manifold One of the purposes and advantages of the instant typeengine is the use of smoothly curved intake manithus making a morehomogeneous charge.

folds 29 as seen in FIGS. 1 and 3. The individual intake manifolds 29are generally equally and symmetrically distributed about the downstreamside of a carburetor casing 34 So arranged, the intake manifold providesa maximum fiow of combustible charge to each cylinder as Well as a moreequal distribution of the charge between the cylinders.

In a conventional internal combustion engine the cylinder head isinternally cored to provide intake manifolding constituted of tortuouspassageways inevitably having a low flow efiicieny due to the frequencyand severity of the curves. It is apparent from FIG. 1 that theindividual intake manifolds 29 provide gently curving air passagewaysbetween the carburetor and each of the cylinders. Since the power anengine can produce is proportional to the quantity of combustible chargedelivered to the cylinders, the efficiency with which the charge isdelivered directly affects power output. cut intake manifoldconstruction results in an increased power output per cycle of theengine.

When the individual intake manifolds are combined in a single casting31, the casting may be secured to the side of the head by studs 32 asshown in FIG. 3.

The cored intake passages 29 formed in the manifold register with thecorresponding air intake passages 26 particularly as shown in FIG. 3.

Referring to the sectional view of FIG. 4, it will be observed that theintake passage 26 is in the general form mixture of fuel and air.

The tangential or tornado swirl imparted to the charge has the addedsalutary effect of throwing the heavier, more difficult to vaporizeparticles against the outer wall of the intake passage where they bettermix with the air The exposure of the charge to the warm passage Walleliminates the necessity of providing exhaust gas or other heat at thecarburetor mounting portion of the intake manifold for fuelvaporization. Thus a considerable saving in cost in manifold manufactureis realized and the nuisance of vapor lock due to poor heat control inhot weather is largely eliminated.

In order to further increase the velocity of the entering charge thecross section of the inner end of the intake passage 26 is reduced orconstricted to provide an annular I venturi 33. The venturi in additionto increasing turbu- Valves Essentially, the improvements in performanceof the present engine over more conventional piston type engines residesin the use of the nested or concentric type inlet and exhaust valves 17and 18. The inlet valve 17 includes a cylindrical or tubular stem ortrunk portion 36 having an annular valve head 37 formed at one endthereof. Valve 17 is reciprocally supported within a valve supportingpassageway formed in the cylinder head 12. The valve supportingpassageway extends completely through the cylinder head and terminatesat the upper and lower faces thereof. The outer peripheral portion 35 ofthe upper face of the valve seat, FIG. 7, is adapted to coact with andseat upon a superadjacent annular edge 38 formed in the cylinder headand to therewith define an annular inlet port 39 for the combustionchamber 24.

A plurality of air holes 41 are provided in the inlet valve trunk 17intermediate the ends thereof. The air Thus the pres- 4 holes are inconstant registry with corresponding holes 42 formed in the exhaustvalve as well as with an air chamber 43 formed in the cylinder head. Thepurpose of the air holes and further details thereof will be discussed,infra, in relation to valve cooling.

The upper end of the inlet valve trunk 36 is externally threaded toreceive a collar 46.

A thin sleeve 47 is press-fitted Within the intake valve trunk toprovide a low friction bearing material within which the exhaust valvemay reciprocate. The sleeve 47 is also provided with air holes inregistry with the holes 41 in the intake valve. A plurality of holes 48provided near the upper end of the valve trunk 36 are internally blockedoff by sleeve 47. The holes 48 are intended merely as recesses adaptedto receive a spanner wrench, not shown, which is used to grip the valvefor the adjustment thereof, infra.

Exhaust valve 18 includes a cylindrical or tubular trunk 51, a webbedvalve supporting portion 52 and a valve head 53. The webbed portion 52may be integral, welded or otherwise affixed to the trunk 51 andincludes an internally threaded support sleeve 54 which is centrallycarried by the webs 56. The valve head 53 includes a stem 55 which isthreadably mounted within the support sleeve 54. While the exhaust valvehead may be otherwise constructed, the present form is preferred for thepurposes of assembling the concentric valves which is most easilyachieved by inserting the tubular exhaust trunk within the intake valvetrunk and thereafter screwing the exhaust valve head into position insleeve 54. When nested Within the inlet valve, the exhaust valve head 53peripherally seats upon the bottom inner edge of the inlet valve head37.

The air holes 42, supra, are formed in the trunk 51 of the exhaust valveproximate the inlet valve air holes 41. It is to be noted that when boththe inlet and exhaust valves are closed the corresponding air holes inthe exhaust and inlet valves are slightly out of phase or registry. Inother words, when the exhaust valve opens relative to the inlet valvethe air holes move toward a more complete registry permitting a greaterquantity of air to flow therethrough. Spanner wrench recesses 57 arealso provided in trunk 51 for adjustment of the amount of exhaust valveopening. A split collar 58 is also threadedly mounted near the upper endof the trunk.

Collars 46 and 58 are adapted to respectively receive one end of thevalve actuating rocker arms 19 and 21. It

is to be noted that as rocker arm 19 opens the inlet valve 17, thecoaction between the valve heads 37 and 53 will cause the exhaust valveto move with but not relative to the inlet valve. On the other hand,actuation of the exhaust valve through rocker arm 21 obviously will notance with the taper of the aforementioned wall and coacts therewith toprovide a venturi 61.

The inner edge of the inlet valve head 37 is similarly upwardly taperedto provide a venturi throat at 62 concentric with venturi 61 formed inthe exhaust valve. Each of the venturis 61 and 6-2, by increasingexhaust gas velocity, creates a significant eductive effect on theexhaust gases thus facilitating scavenging of the combustion chamber.The further utilization of this eductive effect in conjuncwith the valvecooling system will be discussed under the appropriate heading below.

In an engine employing side by side valves, it is necessary to providetwo valve seats in the cylinder head which immediately limits thediametral size to something in the nature of one-half the size that maybe used in the present engines which requires but a single valveopening. It is obvious that such concentric valve arrangement maytherefore result in the use of an intake valve which is one hundredpercent oversize. By making both the inlet and exhaust valve headsoversized there results a better time area diagram otherwise manifestedas a greatly improved volumetric efiiciency. In other words, the largerthe valve the larger the open area through which air may flow in a giventime which represents an important consideration since, as alreadynoted, the power an engine can produce is directly related to the airthat can be packed into the cylinders. The larger intake opening alsoprovides maximum benefit from the velocity-ram effect at the end of theintake period.

Concentric valves also permit placing valve heads at the bot-tom surfaceof the cylinder head thus eliminating shrouding of the valve peripherieswhich is unavoidable with side-by-side poppet valves in the latest typeof combustion chambers.

It is well known expedient to rotate a valve relative to its seat inorder to equalize wear and provide long valve life. To this end it iscommon to incorporate a valve rotating mechanism which in addition toincreasing cost and weight is subject to malfunctioning. In the presentdevice the high velocity tangential or tornado air influx acts on therelatively large (in contrast to a conventional valve stem) tubularvalve surface to rotate the inlet valve relative to its seat. In thepresent construction it is possible that friction between the exhaustvalve trunk 51 and the cylinder head valve supporting passage at 66would create enough circumferential drag on the valve to permit relativerotation between the exhaust valve head 53 and its seat in the inletvalve. However, to insure such relative rotation of the exhaust valverelative to its seat, the ribs or webs 56 of the exhaust valve can beshaped with a slight longitudinal helix. Such helical webs would derivea very powerful rotative reaction effort from the high velocity exhaustgases and would thus insure a rotation of the exhaust valve.

Valve operating mechanism As a means for controlling valve actuation andtiming, the exactness of which determines engine torque and power, thesubject engine utilizes positive valve actuating mechanisms. By thuspositively closing as well as opening the valve longer working andcharging periods are enjoyed with a consequent increase in power output.

The valve actuating mechanism includes cam shaft 22, the inlet andexhaust rocker arms 19 and 21, as well as the collars 46 and 58. Therocker arms are pivotally mounted on fixed shafts 71 and 72 which aregenerally parallel to the cam shaft and the engine centerline.

Each rocker arm includes a bifurcated arm 73 and 74 which engages withinperipheral slots 76 and 77 in the collars 46 and 58. The cam shaft endof each rocker arm also includes a furcate member 78 and 79 adapted torespectively positively engage with opener cam sets 81 and 82 throughfork sets 83 and 84. Similarly closer cam sets 86 and 87 coact with thelower forks 3S and 89.

More specifically, it will be noted that there are two earns 81 and twofollowers 83 coacting to open the exhaust valve and a single cam 86acting on a resilient follower 88 to close the valve. Also two earns 82and two followers 84 are utilized to open the inlet valve while two cams87 coact with two resilient followers 89 to close the valve.

Consideration will be given at this point to the selection of the sevencam and follower arrangements described above.

At first thought, it would be logical to assume that a simple singleeccentric cam could be used for each valve rocker arm to both open andclose the valves. it has been observed, however, that such a device willnot function properly in a forked type rocker arm. This is so becausethe eccentric cam cannot be positioned in such a manner that theangularly disposed follower arms on the forked rocker will maintaincontinuous contact with the eccentric surface throughout the: cycle andprovide the desired periods of valve open and close time. A similardifliculty exists in trying to use a single, special contour cam inplace of the true eccentric. It follows then that it is necessary tooffset the two positions of the rocker arm fork and use one cam and forkhalf for opening the valve and a second cam and fork half for closingthe valve. This results in a total of four cams and followers for thetwo valves, an opener cam and a follower, and a closer cam and afollower for each valve. This mechanism of four cams is apparently thesimplest arrangement which will achieve the desired periods of open andclose time of the valves in a four cycle engine having fully positivelyactuated valves. This arrangement is shown in FIG. 11.

Returning to the preferred embodiment of FIGS. 8 and 9 it will be seenthat there are a total of seven rather than four cams and followers. Thereason for the added number of cams andfollowers is as follows. It is awell known fact in piston engine design that valve operating parts arehighly stressed and that. deflections occur in these parts which resultin faulty valve motion and misalignment of the valve in itsreciprocating motion. The four cam mechanism previously discussed,because the valve operating loads are not symmetrically disposed orbalanced with respect to the valve centerline, would probably be subjectto deflections in the rocker arms which would result in harmful cockingof the valves as they return to their seats. Consequently, threeadditional cams, or a total of seven, are utilized to achieve perfectsymmetry of the valve opening and closing loads thereby avoiding harmfultwisting or cocking type deflections in the rocker arms. Thus, as seenin FIGS. 8 and 9, the opening and closing forks are symmetricallydisposed with respect to the axis of valves.

The resilient members 91 on the valve closing rocker arm forks 88 and 89are employed to exert the force necessary to hold the valves properly ontheir seats. Due to manufacturing tolerances, heat expansions, and othervariables, it is impossible to rely on the closing cams to hold thevalves on their seats with direct mechanical contact at the followers,hence the safety or resilient members. The small space gap 92 betweenthe valve close or follower member and its adjustable seat and springretainer is closed when the valve closer cam is actually operating andthe mechanism then functions as a solid unit.

Each member 91 includes a support sleeve 96 formed on the outerextremity of followers or forks 88 and 89. Slidably mounted in the upperend of sleeve 96 is a cam contacting cap 97 and threadably secured inthe other end of the sleeve is an adjustable plug 98 and a locknut 140.A spring 99 is seated in plug 98 and biases cap 97 upwardly intoengagement with the associated cam. It is apparent that the amount ofgap 92 may be adjusted by threading plug 98 inwardly or outwardly withrespect to sleeve 96 and in this way manufacturing tolerances and wearof the camshaft and rocker arms may be compensated for in order toprevent excessive lash between the rocker arms and the camshaft.

Valve adjusting mechanism As described, supra, there is a threadedportion on the upper end of each valve body onto which is screwed thetwo-piece collars 46 and 58, which as noted, have peripheral groovm 76and 77 into which the ends of the rocker arms 73 and 74 respectivelyengage to translate the rotary motion of the cam members into areciprocating motion at the valve. The adjusting devices on the intakeand exhaust valves are identical, therefore, the description of one suchdevice will suflice. Adjustment of the valve mechanism is necessary inorder to compensate for manufacturing tolerances and for wear of theparts. It will be noted in the valve opening and closing mechanism thatthe valve opening positive acceleration loads are taken by the openerfollowers, but the valve opening negative acceleration loads aretransferred to the so-called closer follower. The converse of thisoccurs in closingthe valve.

and 58 are serrated at 101 in such a manner as to provide a means forengagement by specially serrated wrenches 102 illustrated in FIG. 13. Inadjusting the valves the two pieces 103 and 104 of a collar areseparated from each other by turning them in opposite directions withthe serrated wrenches. After they are loosened, the valve can beadjusted by turning the serrated members while restraining the valvebody from turning by the use of a spanner wrench engaging the spannerrecesses 48 or 57. To obtain the desired adjustment, a shim or gage ofspecific thickness would be inserted between the valve opener cams andtheir respective followers such as to assure that there would be a spacegap between the opener followers and their cams when the valve isseated. Once the valves are properly adjusted, the two collar pieces oneach valve are tightened securely to each other. As shown in FIG. 14,the present device comprehends the use of any well-known type lockingdevice for restraining the two collar pieces against relative movementonce adjusted. Such a locking device could include a thin circular pieceof metal 106 having a plurality of tabs 107 on its periphery which couldbe bent to engage slots in the collar members.

Valve cooling system A further reduction in the size and complication ofthe instant engine is realized by reducing the size and number of coredcooling pasages from that normally required in a fully water cooledengine. To this end a unique air cooling system has been developed tocontrol the temperature of the valve bodies. In this Way a considerablysmaller and lighter cylinder head construction is realized. Referring toFIG. 3 the arrows indicate the path of the cooling air which enters anopening 111 in the cylinder head from a passage 112 leading from anysuitable air cleaner, not shown. The force impelling or drawing airthrough the cylinder head is created by the eduction action whichresults from the expulsion of the exhaust gases from the variouscombustion chambers. As already described in relation to the valves perse, the exhaust valve venturis 61 and 6'2 greatly increase the velocitywith which the exhaust gases are expelled from each combustion chamber.Thus by communicating the exhaust manifolding with the cooling airinlet, through appropriate passages, the cooling air may be drawn overthe valve surfaces to be cooled.

Cooling air is generally drawn down around the exterior of the valvebodies, passing over the rocker arms, thereafter flowing out of thecylinder head through a passage 113 defined by the cylinder head 12, acam shaft cover plate 114 and the engine block 14, and re-entering theblock through passage 116 formed therein, see FIGS. 4 and 12. Passage116 extends through the head and communicates with the air chamber 43from whence some of the air passes directly through the registeringports 41 and 42 in the inlet and exhaust valves progressing over theinner surfaces of the inlet and exhaust valves. A portion of the airflows downwardly through the annular passage 117 to contact the valveheads 37 and 53.

This valve head cooling air is thereafter drawn upwardly and also coolsthe inner wall of the exhaust valve before entering the exhaustmanifold.

An exhaust pipe 118 projects within the exhaust valve terminatingslightly above the exhaust valve head supporting member 52. Pipe 118 isradially spaced from the exhaust valve so as to define therewith anannular air cooling passage 119. A manifold retaining cap 121 and theupper end of the exhaust valve are spaced to form an annular chamber 122connecting with annular passage 119 and a cooling air passage 123 formedin the upper wall of the cylinder head. Thus, air is drawn from passage123 to annular chamber 122 whence it proceeds through passage 119 tocool the inner wall of the exhaust valve.

The cooling air will thus been seen to contact a substantial portion ofboth the inside and the outside valve surfaces by virtue of the variouspaths which the cooling air is made to follow and resulting inconsiderably reduced valve and manifold operating temperatures.

As has been noted, when the exhaust valve is closed air holes 41 and 42are not in full registry reflecting the need for less cooling air atsuch time. However, with the exhaust valve open, the air holes 42 movedownwardly into more complete registry with the inlet valve air holes 41permitting the maximum amount of cooling air to be drawn through thesystem.

There are other reason, now to be considered, which account for what mayappear at first to be the rather devious path followed by the coolingair in the instant engine. In most engines there is the problem ofcontrolling the lubricating oil in the region of the valves to preventleakage therethrough by way of avoiding the carbonizing of the valve.This problem is particularly acute in the instant engine because of theproximity of the cam shaft to the tubular valves. To control the oil inthe instant engine, the rocker arms are closely fitted into the cylinderhead at the top and ends and to each other. This close clearance willprevent any direct splash-through of oil from the cam shaft to the valvecompartment. There will, however, be a certain amount of oil which willtend to creep along the valve end of the rocker arms. This oil wouldfind its way to the valve bodies, run down the clearance space betweenthem and the cylinder head, and result in overlubrication of the valvesand loss of oil. To prevent this, the rocker arms, on the valve side,have been designed with catch basins 126 and protrusions 127, FIG. 8,which will restrain the oil from creeping along the arm and will causeit to be thrown off the arm before it reaches the valves. The stream ofcooling air, referring again to the arrows, on its way to the exhaustvalve eduction venturis will blow this oil through the passage 113 underthe inlet valve rocker arm, back into the cam shaft compartment, anddown along the cam shaft cover plate 114 attached to the cylinder block.Here, as the air suddenly reverses its direction, the oil, by its owninertia, will continue on downwardly into the lower region of theengine. It is intended that the system be designed to permit just enoughoil tocreep to the valve collar members to properly lubricate the armand collar surfaces and the upper end of the exhaust valve, and furtherthat just enough oil will be pulled up to the plurality of holes in thevalve bodies to properly lubricate the rubbing surfaces in this region.

If it is found that an excessive amount of oil is pulled through thevalve body cooling holes, a suitable filter 128 shown in FIG. 12 can beplaced in the air flow path immediately before the air re-enters thecylinder head cored passage 116, so that the excessive suspended oilparticles will be filtered out and drained back to the crank case.

A further object of directing the air over the collared portions of thevalves is to obtain maximum cooling efiect from the quantity used and toeliminate the risk of thermal shock to the hotter regions of the valve.Thus the cold entering air serves to cool the mildly hot upper andmiddle regions of the valve and then proceeds, by its round-about path,to the hotter lower regions where it completes the valve cooling withoutrisk of thermal shock to the parts contacted.

The present exhaust valve manifold network, supra, as combined with theair cooling arrangement constitutes a continuously open valve coolingsystem. In other words a partial vacuum is maintained in the exhaustmanifold at all times, thus cooling air is being continuously drawnthrough and over the valve stem surfaces, as described above, eventhough a particular exhaust valve is momentarily closed. The continuousflow of cooling air past the exhaust venturi 62 makes possible theuninterrupted inertia flow of an exhaust gas or air column through theexhaust passage 27 thus avoiding the inefiicient alternate stopping andstarting of the column at each opening and closing of the exhaust valveas occurs in a conventional engine. In this way, the moment the exhaustvalve cracks open the air column being continuously drawn through theexhaust passage begins a powerful extraction of the exhaust gases fromthe combustion chamber resulting in highly efficient combustion chamberscavenging.

The instant engine also utilizes a liquid cooling system for coolingthose parts of the engine not adequately cooled by the air system.Accordingly, cored liquid coolant passages such as 131 and 132 areformed in the cylinder head and are supplied with liquid to facilitatethe more complete cooling of the combustion chamber area.

The jet-induced air cooling of valves and air shielding of the new andoriginal passage for exhaust gas greatly reduces requirements forstandard cooling equipment on the engine, i.e., smaller cooling fan,smaller quantity of coolant on liquid cooled engines, as well as simplerfinning and less air circulation on air cooled engines. Further, thehigh velocity exhaust gas and jetinduction of cooling air permits theuse of a cheap, thin- Walled, fabricated exhaust manifolding in contrastto the expensive, heavy and bulky cast manifolds used on most engines.This cheap, thin-Walled exhaust manifolding incorporates individual,highly efiicient, smooth turn branches from each cylinder ofmulti-cylinder engines to common union with a large main exhaustmanifold 129 to provide continuous jet-induction of fresh air to thevalve cooling passage of each cylinder at all times.

Exhaust manifold An important reason for the high efficiency of thepresent engine resides in the ability to utilize an exhaust manifoldhaving a high flow efficiency. As particularly seen in FIG. 3 thestraight-up exhaust passage 27 combined with a smoothly curving exhaustmanifold 28 appreciably reduces the frictional flow losses encounteredin the conventional tightly curved exhaust passage. The manifolding asdescribed makes possible the use of more efiicient and cheaper devicesfor the conversion of exhaust gas velocity energy into useful work-moreefficient because of higher gas velocity and cheaper because of loweroperating temperatures.

The new type exhaust manifold also permits the design, for heavy dutyoperation, of a simple and cheap turboevacuator device for supplementingthe jet-induction of air through the valve cooling system, or the designof turbo-driven superchargers for supercharging the engine or forcooling engine components, or the design of turbodriven devices forcompounding the power of the engine.

Combustion chamber The cylinder head 12 overlies the cylinder peripherysufiiciently to enable the former to coact with the piston 16 to definea full circumference squish area 136. The tornado swirl of the incomingcharge, as already noted, provides a completely homogeneous mixture offuel and air which with the large squish area combine to yield betterdetonation control at high compression ratios.

The concentric valves centrally located within the sur- 10 roundingsquish area provide maximum benefit from valve timing overlap inclearing the chamber of burned gas resulting in less dilution of thecharge and a lower mixture temperature.

A recess 137 is provided in the cylinder head which is bored at theinner end to receive a spark plug 138. The squish area around the sparkplug is specially shaped at 139 to fire a flame trigger into theturbulent charge. Particularly in the present compact combustionchamber, the extremely turbulent charge coupled with the squishedtrigger flame propagation provides a very fast and yet smooth burning ofthe charge at extra high compression ratios.

The compact combustion chamber with the concomitantly smaller heat lossresulting from the diminution in size promotes greater work recovery perexplosion, higher thermal efficiency and accordingly greater fueleconomy.

The tangential port and concentric valve arrangement provides maximumbenefit from the blast cleaning of the combustion chamber and valves ofcarbon deposits without removing the cylinder head from the engine.Also, the concentric valve arrangement placing the valve heads at thebottom of the cylinder head makes possible the grinding of the valvesWithout removing the valves from the cylinder head.

While the present invention has been disclosed as including specifictypes of components and arrangements of components it is apparent thatmany structural and orientation modifications with respect to thecomponents are comprehended within the scope of the invention.

I claim:

1. A valve actuating mechanism for an internal combustion engine whichcomprises a rocker arm mounted proximate said valve and operativelyconnected directly thereto, a rotary cam shaft operatively connected tosaid rocker arm, said rocker arm being pivotally mounted on a shaftgenerally parallel to the cam shaft and including a first bifurcatedportion adapted to operatively engage said valve, valve opening andclosing cams: on said cam shaft, said rocker arm including a secondfurcated portion having at least one fork engaging an opening cam and atleast another fork engaging a closing cam whereby said valve ispositively opened and closed, and resilient means intermediate theclosing cam and said another fork to insure closing of said valve.

2. An internal combustion engine including in combination a cylinderhead, a pair of concentric air valves reciprocally supported in saidhead, and an actuating mechanism for said valves, said mechanismcomprising a cam shaft having a plurality of axially spaced valveopening and closing cams, a rocker arm for each valve pivotally mountedon a shaft generally parallel to the cam shaft intermediate the latterand the valves, each rocker arm including a first bifurcated portionadapted to circumferentially engage one of said valves, a secondfurcated portion having a set of forks respectively engaging saidopening cams and at least one fork engaging a closing cam, and meansmounted on each of said valves for adjusting the stroke of said valvesWithin said cylinder head.

3. An internal combustion engine including in combination a cylinderhead, a pair of concentric air valves reciprocally supported in saidhead, and an actuating mechanism for said valve, said mechanismcomprising a cam shaft having a plurality of axially spaced valveopening and closing cams, a rocker arm for each valve pivotally mountedon a shaft generally parallel to the cam shaft intermediate the latterand the valves, each rocker arm including a first bifurcated portionadapted to circumferentially engage one of said valves, a secondfurcated portion having a set of forks respectively engaging saidopening cams and at least one fork engaging a closing cam, means mountedon each of said valves for adjusting the stroke of said valves Withinsaid cylinder head and 1 1 means associated with each rocker arm formaintaining said forks in engagement with said cams.

4. An internal combustion engine including in combination a cylinderhead, a stemmed air valve supported Within said head, a split collarmounted on the stem of said valve, a pivoted rocker arm having one armin operative engagement with said collar and means for causing a rockingmovement to be imparted to said rocker arm, said collar comprising apair of elements severally movable relative to the valve stem, saidmembers being normally in abutting relation, means for axially movingeach of said collar members relative to each other in order to adjustthe length of stroke of said valve and means for restraining said valveagainst rotation when changing the axial positions of said collarelements relative to said valve.

5. A valve actuating mechanism for an internal combustion engine whichincludes a pair of concentric intake and exhaust valves, said mechanismcomprising a rocker arm operatively connected to each of said valves,each rocker arm being pivotally mounted intermediate its ends on ashaft, said shafts being disposed one above the other in parallelrelation, and a camshaft drivingly connected to said rocker arms, eachrocker arm including a first bifurcated portion circumferentiallyengaging the associated valve, said arms including second bifurcatedportions operatively engaging said camshaft to positively open and closesaid valves, said second bifurcated portions of the rocker arms beingsymmetrically disposed with respect to the axis of said valves toprevent cocking of the valves during actuation thereof.

6. A valve actuating mechanism as described in claim 5 in which each ofsaid second bifurcated arm portions 12 includes a plurality of forkswhich coact with valve opening and closing cams on said camshaft, and atleast one of said forks on each arm including resilient means forautomatically maintaining said forks in contact with the related cams.

7. A valve actuating mechanism as defined in claim 6 in which saidresilient means comprises a cylinder formed on said fork, a pistonreciprocally disposed in said cylinder and resilient member intermediatesaid cylinder and piston tending to bias said piston into engagementwith the related cam.

References Cited in the file of this patent UNITED STATES PATENTS1,157,379 Gibbs Oct. 19, 1915 1,232,108 Sims July 3, 1917 1,311,200Abell July 29, 1919 1,399,283 Zucker Dec. 6, 1921 1,408,781 Sewell Mar.7, 1922 1,671,973 Anderson June 5, 1928 1,754,888 Gerard Apr. 15, 19302,049,186 Zahodiakin July 28, 1936 2,122,806 Abell July 5, 19382,213,202 Buchi Sept. 3, 1940 2,252,171 Doman Aug. 12, 1941 2,277,822Essl Mar. 31, 1942 2,428,886 MacPherson Oct. 14, 1947 2,457,652 FisherDec. 28, 1948 2,840,059 Buchi June 24, 1958 FOREIGN PATENTS 268,602Great Britain Apr. 7, 1927 1,029,745 France Mar. 11, 1953

